News About Pollutionhttp://www.terradaily.com/Froth_And_Bubble.html
News About PollutionMon, 14 AUG 2017 15:29:05 AESTMon, 14 AUG 2017 15:29:05 AESTen-us
Gabes, Tunisia (AFP) Aug 11, 2017 -
Next to a palm grove, a blackish mud flows into the sea. After years of living with industrial pollution, residents of Tunisia's Gabes are fighting back.

Close to the Chott Essalem beach and in front of a rare coastal oasis, the state-owned Tunisian Chemical Group (GCT) has been processing phosphate since the 1970s.

The authorities say the plant pumps 14,000 tonnes of phosphogypsum into the sea every day. On top of the toxic mud, the factory also pumps phosphoric acid into the air.

"In the past, our town was clean," says Moncef Ben Ayadi, a 52-year-old carpenter who lives in Nezla, close to the plant.

But "since the company arrived, Gabes has become a victim city".

Residents blame it for a long list of woes: chronic fatigue, breathing problems, pollution of the water and soil, and destruction of biodiversity.

Many are sure that pollution from the factory is the cause of a local surge in cancer cases, a claim the government rejects.

"According to studies carried out by the health ministry, there is no causal relationship between illnesses such as cancer and asthma and the pollution caused by the chemical plant," the governor of Gabes, Mongi Thameur, told AFP.

But many residents are sceptical.

Sabeh Moumen, 47, a local restaurateur, is convinced her asthma was caused by the pollution.

Still mourning her brother's death from cancer three months ago, Sabeh says that in Gabes, "we no longer have any hope of living in a clean environment or eating anything healthy".

The Gulf of Gabes is an important spawning ground for Mediterranean fish.

But phosphate mining and processing, industries that are important for Tunisia's economy, have left it heavily polluted.

- Ending the silence -

The question was long off limits for discussion.

Under the dictatorship of veteran president Zine El Abidine Ben Ali, "it was forbidden to talk of environmental crimes committed by the complex, on the pretext that it was a source of national wealth," says Kheireddine Debaya, 32, an activist with "Stop Pollution", a local campaign group.

But since Ben Ali's overthrow in a 2011 revolution that sparked the Arab Spring uprisings, the silence has been broken.

Campaigners have organised protests and demanded the complex be relocated.

They have protested by setting up tents in front of an entrance to the complex.

"The situation is catastrophic," says Khaled Hassanet, 24, who is taking part in a sit-in outside the building.

"The state has prioritised its economic interests to the detriment of people's health," he adds, as thick white smoke billows from the production units.

The authorities say they are taking steps to address the issue.

In late June, Prime Minister Youssef Chahed said the complex would be gradually dismantled and replaced by a "new industrial zone conforming to international (environmental) standards".

The project is expected to cost between $1.4 and $1.6 billion and take at least eight years.

The location of the new site is to be decided by December.

"With this project, the Gulf of Gabes and its beaches, including Chott Essalem, will be liberated," Thameur says, adding that it could attract tourists in the future.

But activists have their doubts.

"There are no guarantees," Debaya says.

"For years, there have been decisions and promises, but they've never been carried through."

]]>

Mon, 14 AUG 2017 15:29:05 AEST
Washington (AFP) Aug 10, 2017 -
The Earth set a series of dire records in 2016, including hottest year in modern times, highest sea level and most heat-trapping gases ever emitted, a global climate report said Thursday.

A range of key climate and weather indicators show the planet is growing increasingly warm, a trend that shows no signs of slowing down, said the annual State of the Climate Report.

"Last year's record heat resulted from the combined influence of long-term global warming and a strong El Nino early in the year," said the report.

"The major indicators of climate change continued to reflect trends consistent with a warming planet," it added, noting that several markers -- such as land and ocean temperatures, sea level and greenhouse gas concentrations in the atmosphere -- broke records set just one year earlier.

The ominous news comes two months after President Donald Trump announced the United States would withdraw from the 2015 Paris accord on global warming, a decision that sparked widespread international criticism.

In the past billionaire Trump has called climate change "a hoax" invented by the Chinese, dismissing scientific evidence of human contributions to rising temperatures.

But as humanity continues to rely on fossil fuels for energy unprecedented levels of greenhouse gases are polluting the atmosphere, acting like a blanket to capture heat around the Earth, the report emphasized.

All the major greenhouse gases that drive warming, including carbon dioxide (CO2), methane and nitrous oxide, rose to new heights, it said.

Atmospheric CO2 concentration reached 402.9 parts per million (ppm), surpassing 400 ppm for the first time in the modern record and in ice core records dating back as far as 800,000 years.

"Climate change is one of the most pressing issues facing humanity and life on Earth," said the peer-reviewed publication, put together by nearly 500 scientists around the globe and released each year by the National Oceanic and Atmospheric Administration and the American Meteorological Society.

The entire 280-page report is available online.

- Hottest year -

The report confirmed prior announcements that 2016 was the hottest year since contemporary records began, marking the third year in a row that global records were broken planet-wide. Both land and sea surface temperatures set new highs.

Melting glaciers and polar ice caps swelled the world's oceans, and global average sea level rose to a new record high in 2016 -- about 3.25 inches (82 millimeters) higher than the 1993 average.

Global sea level has risen for six straight years, with the highest rates of increase seen in the western Pacific and Indian Oceans.

In the sensitive polar regions, sea ice in both the Arctic and Antarctic hit record lows.

Some extreme weather events increased, such as unusually high tropical cyclone activity. A total of 93 named tropical cyclones were observed worldwide in 2016, well above the 1981-2010 average of 82 storms.

Record high annual temperatures swept Mexico and India.

Over the northern and eastern Indian peninsula, a week-long heat wave at the end of April saw temperatures exceed 111 F (44 C), contributed to a water crisis for 330 million people and to 300 fatalities, the report said.

Meanwhile, drought was unusually widespread. At least 12 percent of land surfaces experienced severe drought conditions or worse each month of the year.

"Drought in 2016 was among the most extensive in the post-1950 record," said the report.

Northeastern Brazil marked its fifth consecutive year of drought, the longest dry spell on record in this region.

Meanwhile, the weather phenomenon known as El Nino, which warms waters around the equator in parts of the Pacific, was strong in the first half of 2016, leading to increasingly wet conditions in some places.

Argentina, Paraguay, and Uruguay saw repeated heavy flooding, while parts of eastern Europe and central Asia were also wetter than usual.

The US state of California had its first wetter-than-average year since 2012, breaking a drought that lasted several years.

]]>

Mon, 14 AUG 2017 15:29:05 AEST
Blacksburg VA (SPX) Aug 09, 2017 -
Environmental scientists led by the Virginia Tech College of Science have discovered that the burning of coal produces incredibly small particles of a highly unusual form of titanium oxide.

When inhaled, these nanoparticles can enter the lungs and potentially the bloodstream.

The particulates - known as titanium suboxide nanoparticles - are unintentionally produced as coal is burned, creating these tiniest of particles, as small as 100 millionths of a meter, said the Virginia Tech-led team. When the particles are introduced into the air - unless captured by high-tech particle traps - they can float away from power plant stacks and travel on air currents locally, regionally, and even globally.

As an example of this, these nanoparticles were found on city streets, sidewalks, and in standing water in Shanghai, China.

The findings are published in the latest issue of Nature Communications under team leader Michael F. Hochella Jr., University Distinguished Professor of Geosciences with the College of Science, and Yi Yang, a professor at East China Normal University in Shanghai. Other study participants include Duke University, the University of Kentucky, and Laurentian University in Canada.

"The problem with these nanoparticles is that there is no easy or practical way to prevent their formation during coal burning," Hochella said, adding that in nations with strong environmental regulations, such as the United States, most of the nanoparticles would be caught by particle traps. Not so in Africa, China, or India, where regulations are lax or nonexistent, with coal ash and smoke entering the open air.

"Due to advanced technology used at U.S.-based coal burning power plants, mandated by the Clean Air Act and the Environmental Protection Agency, most of these nanoparticles and other tiny particles are removed before the final emission of the plant's exhaust gases," Hochella said.

"But in countries where the particles from the coal burning are not nearly so efficiently removed, or removed at all, these titanium suboxide nanoparticles and many other particle types are emitted into the atmosphere, in part resulting in hazy skies that plague many countries, especially in China and India."

Hochella and his team found these previously unknown nanoparticles not only in coal ash from around the world and in the gaseous waste emissions of coal plants, but on city streets, in soils and storm water ponds, and at wastewater treatment plants.

"I could not believe what I have found at the beginning, because they had been reported so extremely rarely in the natural environment," said Yang, who once worked as a visiting professor in Virginia Tech's Department of Geosciences with Hochella. "It took me several months to confirm their occurrence in coal ash samples."

The newly found titanium suboxide - called Magneli phases - was once thought rare, found only sparingly on Earth in some meteorites, from a small area of rock formations in western Greenland, and occasionally in moon rocks. The findings by Hochella and his team indicate that these nanoparticles are in fact widespread globally. They are only now being studied for the first time in natural environments using powerful electron microscopes.

Why did the discovery occur now? According to the report, nearly all coal contains traces of the minerals rutile and/or anatase, both "normal," naturally occurring, and relatively inert titanium oxides, especially in the absence of light.

When those minerals are burned in the presence of coal, research found they easily and quickly converted to these unusual titanium suboxide nanoparticles. The nanoparticles then become entrained in the gases that leave the power plant.

When inhaled, the nanoparticles enter deep into the lungs, potentially all the way into the air sacs that move oxygen into our bloodstream during the normal breathing process. While human lung toxicity of these particles is not yet known, a preliminary biotoxicity test by Hochella and Richard Di Giulio, professor of environmental toxicology, and Jessica Brandt, a doctoral candidate, both at Duke University, indicates that the particles do indeed have toxicity potential.

According to the team, further study is clearly needed, especially biotoxicity testing directly relevant to the human lung. Partnering with coal-power plants either in the United States or China would be ideal, said Yang.

More troubling, the study shows that titanium suboxide nanoparticles are biologically active in the dark, making the particles highly suspect. Exact human health effects are yet unknown.

"Future studies will need to very carefully investigate and access the toxicity of titanium suboxide nanoparticles in the human lung, and this could take years, a sobering thought considering its potential danger," Hochella said.

As the titanium suboxide nanoparticle itself is produced incidentally, Hochella and his team came across the nanoparticle by accident while studying a 2014 coal ash spill in the Dan River, North Carolina. During the study of the downstream movement of toxic metals in the ash in the Dan River, the team discovered and recognized the presence of small amounts of the highly unusual titanium suboxide.

The group later produced the titanium suboxide nanoparticles when burning coal in a lab simulation.

This new potential air pollution health hazard builds on already established findings from the World Health Organization. It estimates that 3.3 million premature deaths occur worldwide per year due to polluted air, Hochella said. In China, 1.6 million premature deaths are estimated annually due to cardiovascular and respiratory injury from air pollution. Most Chinese megacities top 100 severely hazy days each year with particle concentrations two to four times higher than WHO guidelines, Yang said.

Direct health effects on humans is only one factor. Findings of thousands of scientists have determined that the biggest driver of warming of the planet and the resulting climate change is industrial-scale coal burning. The impact of titanium suboxide nanoparticles found in the atmosphere, in addition to greenhouse gases, on animals, water, and plants is not yet known.

Mon, 14 AUG 2017 15:29:05 AEST
Los Angeles CA (SPX) Aug 09, 2017 -
In a groundbreaking study released this week, scientists at the South Coast Air Quality Management District and the University of Southern California have found that widespread installation of certain "cool roof" materials in the region could slightly increase ozone and fine particulate pollution levels.

The study explains how the predicted increase in ozone levels can be minimized or possibly avoided by requiring more comprehensive performance standards for cool-roofing materials. However, small increases in fine particulate (PM2.5) levels are predicted to occur with or without enhanced standards.

"Cool roofs have many benefits including reduced energy use for cooling and mitigation of the significant health impacts of heat waves." said Wayne Nastri, SCAQMD's executive officer.

"While the future, widespread use of certain kinds of cool roofing materials could slightly increase air pollution levels, we in no way want to discourage this technology. This study shows what needs to be done to help cool our cities and avoid increasing ozone levels as an unintended consequence."

The study, titled "Air Quality Implications of Widespread Adoption of Cool Roofs on Ozone and Particulate Matter in Southern California," was published in the Proceedings of the National Academy of Sciences.

The scientific paper was produced by a team of SCAQMD scientists led by Scott A. Epstein, Ph.D., in collaboration with George Ban-Weiss, Ph.D., a professor of civil and environmental engineering at USC. They used sophisticated meteorology and air quality computer models, measurements of cool roofing materials and detailed databases of the region's rooftops to predict the air quality impacts of the increasing use cool roof materials - typically light-colored and highly reflective - that are expected to result from current statewide energy efficiency standards.

Numerous scientific studies have established that replacing darker roofs and building materials with highly reflective materials can reduce peak daytime temperatures and mitigate the so-called "urban heat island effect" where cities can be several degrees warmer than less-urbanized surrounding areas.

However, many cool-roofing materials reflect more ultraviolet light (UV) than their traditional counterparts, increasing the potential for ozone formation. UV rays fuel smog formation on their way down to Earth. When cool roofs bounce UV rays back up into the atmosphere they create a "double-shot" of ozone formation.

This ozone increase can be avoided if a comprehensive roofing standard is adopted to prevent the overall UV reflectance of newly-installed cool roofs from increasing. Cool roofing materials are available today that reflect the same amount or even less UV than traditional, roofing materials.

"This study highlights the importance of considering how strategies used to mitigate one environmental issue can have co-benefits and/or unintended consequences on other environmental systems," Ban-Weiss said. "Whether air pollution improves or worsens from cool roof installations depends on a host of competing chemical and meteorological factors.

"Given that our study focuses on the Los Angeles basin, future research is needed to investigate how these competing processes dictate air pollution impacts in cities around California and beyond."

While an increase in ozone formation can be mitigated by changing cool roofing materials, the predicted small increase in PM2.5 levels is due to overall cooler surface temperatures resulting in weaker sea breezes and lower inversion layers, and will occur regardless of UV reflectance of roofing materials, according to the study.

The study also noted the installation of cool paving materials could have an even bigger impact on ozone and PM2.5 levels since the amount of area paved in the region is significantly larger than the total roofing area affected by state energy efficiency standards.

]]>

Mon, 14 AUG 2017 15:29:05 AEST
Raleigh NC (SPX) Aug 09, 2017 -
A recent study from North Carolina State University finds that advanced wood-burning stoves designed for use in the developing world can reduce air pollution more than anticipated, because gaseous emissions from traditional wood stoves form more particulate matter in the atmosphere than researchers previously thought.

"Previous studies have looked solely at direct emissions from cookstoves," says Andrew Grieshop, an assistant professor of civil, construction and environmental engineering at NC State and corresponding author of a paper describing the work. "We've now done a series of experiments to determine what happens to those emissions while they are in the atmosphere."

At issue is particulate matter (PM): minute, airborne particles that can contribute to human health problems, such as asthma.

For this study, researchers tested three types of wood-burning stoves: traditional stoves; natural-draft stoves; and forced-draft stoves, which use battery-powered fans to improve combustion.

The researchers collected emissions from each of the stoves and used an environmental chamber and a custom-built oxidation flow reactor to mimic the chemical reactions that would normally take place with the emissions over the course of up to two weeks in the atmosphere.

The researchers found that, while traditional stoves emitted an average of 6 grams of PM per kilogram of fuel burned (g/kg), that number jumps to an average of 14 g/kg when you include the PM that the emissions form over time, due to chemical reactions that take place in the atmosphere.

Natural-draft stoves, by comparison, produced an average of about 4 g/kg of PM - even after aging in the atmosphere. And forced-draft stoves produced less than 3 g/kg.

"All of this is based on lab measurements, which is important to note because previous studies have found that advanced stoves don't necessarily work as well in the field as they do in the lab," Grieshop says.

"However, the study does tell us that looking solely at stove emissions at the point of use doesn't give us a full picture of what's going on. The effects of atmospheric chemistry are extremely important to understanding the potential air quality benefits."

And the effects of the stove technologies on global climate change are even more complicated.

Advanced stoves are more efficient than traditional ones. So, for example, advanced stoves require less wood to boil a pot of water. However, kilogram of wood for kilogram of wood, advanced stoves produce PM that absorbs more light than PM from traditional stoves, which produce more reflective PM. Absorbing PM can make a large contribution to atmospheric warming, while reflective PM can offset it.

"There are a lot of variables involved when it comes to evaluating the effects of these emissions on global climate change, but it's an interesting finding that should be taken into consideration when modeling the effect of both traditional and advanced stove technologies on the climate," Grieshop says.

Mon, 14 AUG 2017 15:29:05 AEST
Phnom Penh (AFP) July 13, 2017 -
Cambodia has outlawed sand exports from a coastal region where it has been primarily funnelled in huge quantities to Singapore, a move met with scepticism from activists who said previous bans on the destructive industry had failed to take root.

Environmental groups have long accused Cambodia of running damaging and corrupt sand dredging operations along the southwest coast and the Mekong river.

Most of the sand has been shipped to Singapore to fuel the wealthy city-state's rapid expansion -- a resource plunder that activists say has devastated local Cambodian communities and ecosystems.

The new decree, issued on July 10, bars all exports of "construction sand and mud sand" from southwestern Koh Kong province to overseas but stops short of outlawing domestic sales.

It was issued in response to environmental concerns, said Meng Saktheara, a spokesman for Cambodia's mining and energy ministry.

"If we continue to allow large-scale sand dredging (in Koh Kong) for exports, it would hugely affect the natural environment and local communities," he told AFP.

Environmental activists welcomed the move but expressed doubt it would fully halt a trade that has survived previous bans.

"There has been such a ban in recent years, but they (companies) still operated and exported," said Meng Heng, from the environmental group Mother Nature.

The new directive comes after Phnom Penh temporarily suspended sand exports in November following controversy over large discrepencies in Cambodian and Singapore trade records for how much of the commodity was being shipped.

Environmental groups say illegal exports have continued despite that order.

Koh Kong province is the main region where sand is excavated and shipped to foreign countries, according to Meng Heng.

But there are also concerns about damage wrought from dredging along the Mekong River.

"We want a ban of exports of sand from the whole country, including sand from the Mekong river," he said.

Their efforts came as the government said around 1,000 tonnes of the solidified oil had spilled from a cargo ship after a collision with another vessel near the Pearl River estuary in southern China Thursday.

It was the first time authorities had confirmed how much had been spilled.

Thirteen of the city's most popular swimming spots are closed after white clumps of the oil started appearing Sunday.

Official cleaning teams have been sent to clear it from beaches and surrounding waters.

But criticism of the government's response is mounting.

On Wednesday afternoon a team of local volunteers from Lamma Island in the south of Hong Kong braved sweltering heat and humidity to comb one of the worst-affected beaches, filling black bin bags with the lumps of oil.

A sour stench hung over the area and small numbers of dead fish were washing in.

The surrounding pathways were slippery with oil that had melted as temperatures hit 33 degrees Celsius (91 degrees Fahrenheit).

"The government should put in more effort to clean up. I'm here because no one else is doing it," Tony Mok, 31, told AFP.

"Every morning it looks like it has snowed in Hong Kong, and every afternoon it's all melted back down under the sand," said Lamma resident Robert Lockyer, who was leading the two dozen volunteers working to remove the oily white clumps.

Aleli Pena, 38, described the clean-up effort as "hard, hot and disgusting".

"We're all volunteers -- where are you government?" she asked.

- Too little, too late? -

Others said government cleaners had been working hard, but questioned why more had not been done to intercept the oil before it reached the beaches.

Environment campaigner Gary Stokes said the government should have installed pollution booms -- a kind of floating barrier -- to stop the oil reaching the beaches.

Stokes, Asia Director for Sea Shepherd Conservation Society, has written to the marine department asking them to install the booms to guard against more oil washing in.

Tse had said earlier that he would not rule out the oil spreading to other areas.

The government has repeatedly described the palm oil as non-toxic and "harmless" to humans.

"You will see that many instant noodles have palm oil in them," Tse said Wednesday, although he acknowledged a large amount would affect the environment.

Stokes said the oil was hazardous to wildlife because it attracts bacteria and had left a greasy film on the water which would reduce the supply of oxygen.

After examining the waters by boat himself, he told AFP the fish were "going crazy" for the lumps of oil and eating it, with unknown consequences.

The government has been questioned over why it was not notified by mainland authorities until Saturday of the Thursday spill.

Tse said it was only then that Chinese authorities realised it would spread to "other regions".

The marine department then dispatched ships to try to recover some of the oil, he said.

So far 50 tonnes had been gathered in Hong Kong and 38 tonnes in Guangdong, Tse added.

The spreading algae, which contain a toxin that can irritate the skin, have produced a greenish brown hue in the waters off some beaches of the hugely popular archipelago near the coast of Africa that attracts millions of visitors every year.

But Jose Juan Aleman, director of public health for the archipelago, told AFP that no beach had "been closed in the Canaries due to the presence of microalgae".

"When microalgae are detected in a bathing zone, swimmers are recommended not to touch them," he said.

On Tuesday a red flag flew on part of Tenerife's Las Teresitas beach -- meaning swimming was not allowed.

A yellow flag -- urging precaution -- flew on the other section of the beach.

"This morning, we detected a lot of microalgae on the beach and we decided to put up the red flag," a Red Cross lifeguard, who refused to be named, told AFP.

But despite the ban, holidaymakers were still seen swimming.

"We've been giving information all day and blowing the whistle, we get them out of the water and then they just come back," he said.

Others played football on the beach, where traces of the algae and foam could be seen.

The algae are a type of bacteria, trichodesmium erythraeum, also known as sea sawdust, Aleman told AFP on Monday.

"Its proliferation is a natural, temporary phenomenon which is going to disappear" in due course, he added, suggesting global warming was helping the algae spread.

The bacterium "contains a toxin which can lead to skin irritation, dermatitis, hence one must avoid coming into contact with it in the water and on the sand."

Those include "an increase in water temperature" as well as a "dust cloud sweeping in off the Sahara which is rich in iron, a nutrient which micro-organisms like".

]]>

Mon, 14 AUG 2017 15:29:05 AEST
Hong Kong (AFP) Aug 7, 2017 -
A clean-up operation was under way in Hong Kong Monday after a massive palm oil spillage from a ship collision in mainland Chinese waters clogged some of its most popular beaches.

The coast was coated with rancid-smelling sticky white clumps of the oil as it washed in Sunday, with 11 beaches still closed to swimmers Monday in the height of a summer heatwave.

There are still lumps of the solidified oil on the beaches and the sea water in some areas is greasy.

Hong Kong comprises more than 200 islands with glittering bays, but there are increasing concerns about pollution and rubbish blighting its shores.

On Pui O beach, on the island of Lantau, cleaners raked through the famous black sand Monday morning retrieving lumps of palm oil mixed with other trash, from plastic water bottles to children's toys.

Although there is still a red flag up and the beach is officially closed, some people still ventured into the water.

One 61-year-old surfer, who gave his name as Simon and is a regular at the beach, said there was still oil in the water.

"It got under my feet and on my board. It's all slippery," he told AFP.

"Yesterday there was big chunks along the beach and in the water."

He added that there was often rubbish on the beach, often left by visitors.

"I live here now, I have to put up with it. I don't like it," said Simon, who is an airport worker originally from Hawaii.

Beach announcements told determined swimmers at the closed beaches to get out of the water Monday.

But Agnes Mercado, 49, a regular at secluded South Bay on Hong Kong Island, was determined to take her morning dip, although she said she would not submerge her upper body.

"Of course I'm worried about it, but it's even worse than this on some days," she said of the pollution.

The Leisure and Cultural Services Department said beach workers were using absorbent strips to prevent the spread of the oil and that government departments had been notified to clean up the water.

In a statement late Sunday it described the palm oil as "harmless to the human body".

But environmentalists still fear the potential impact and say the government has not done enough to contain the spillage.

"Whilst we may not see birds covered in black oil, palm oil is hazardous to wildlife in that it attracts bacteria," said Gary Stokes of the Sea Shepherd Conservation Society.

Stokes added that the oil will dissolve and break down, which could also remove oxygen from the water and kill marine life.

Swathes of rubbish frequently clog the coastline with authorities and environmentalists pointing the finger at southern mainland China as the source.

However, campaigners also say Hong Kong itself has a terrible track record on dumping of waste -- the city's landfills are groaning at capacity and there is no widespread recycling culture.

Tenerife in particular is awash with visitors at this time of year but some of those having an Atlantic dip have come out scratching themselves after brushing up against the tiny algae.

The spreading algae have produced a greenish brown hue in the waters off some beaches in the tourist haven.

"Since the end of June, we have seen episodes of massive efflorescence (or bloom) of microalgae, sometimes reaching as far as bathing beaches," Jose Juan Aleman, director of public health for the Canaries, told AFP.

The algae are a type of bacteria, trichodesmium erythraeum, also known as sea sawdust, said Aleman.

"Its proliferation is a natural, temporary phenomenon which is going to disappear" in due course, he added, suggesting global warming was helping the algae spread.

The bacterium "contains a toxin which can lead to skin irritation, dermatitis, hence one must avoid coming into contact with it in the water and on the sand."

With the islands last year welcoming more than 13 million foreign tourists, local authorities were keen to reassure sun-seekers.

"Generally, it has not been necessary to close the beaches," said Aleman.

However, AFP found that several have been closed to swimmers over recent weeks, including the popular Teresitas beach at Santa Cruz de Tenerife.